Developmental variations in the peripheral erythrocytic system of the rainbow trout, Salmo gairdneri

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Abstract

The peripheral circulating erythrocytic system of the
rainbow trout, l3 almo gairdner , was examined in vitro in relation differences in the morphology and multiple hemoglobin system
organization of adult and juvenile red cells.
Cells were separated by velocity sedimentation under unit
gravity, a procedure requiring red cell exposure to an incubation
medium for periods of at least three hours. Therefore ,
this must provide an environment in which red cells remain in a
condition approximaing normalcy. Previous studies having
demonstrated commonly employed media to be ineffective in this
regard , a medium was developed through modification of Cortl and
saline. One of the principal additions to this me dium ,
norepinephrine, altered cell regulation of intracellular calcium,
magnesium and chloride concentrations. Catecholamine involvement
was also suggeste d in the synthes is of hemoglobin .
The procedure was found to separtate cells primarily by
density and, to a lesser extent, by shape. Characterization of
red cells revealed two subpopulations to exist . The first
comprised the bulk of the cell population, and were of greater
l ength, width, volume and major:minor axis ratio than the smaller
population; these were adult cells. The later, juvenile cells
were of smaller overall size and were more spherical in shape .
Juvenile cells also possessed fewer electrophore tpically distinguishable
isomorphs than did adults with only eight of
eleven hemoglobin component s typically found With maturation,hemoglobin complement with the development of three more bands.
The total complement of the adult cell contained 7 cathodal bands
and four anodal hemoglobin isomorphs. Bands acquired with
maturation comprised the smallest percentage of the cells
hemoglobin. each averaging less than one-percent of the
total. Whether these additional bands are derived through
degradation and reaggregation of existing components or are the
product of pe gQy2 synthesis is not yet known.